Certainly with DRMed video it is common for the video to never be buffered/stored on disk. Sometimes a few seconds is, but even that is uncommon, and more likel

Certainly with DRMed video it is common for the video to never be buffered/stored on disk. Sometimes a few seconds is, but even that is uncommon, and more likely it would simply be retained in RAM now. With more secure DRM systems the OS literally never gets access to the video buffer, protected by hardware, in order to even send it to disk.